An endopylotomy is performed to expand the size of a lumen of a patient's ureter to enable, for example, passage of stones and/or stone fragments through the lumen. Constriction of the ureter lumen may be caused at the uretero-pelvic junction (UPJ) from pressure created by crossing vessels, such as, the femoral artery and/or vein. Surgical intervention is often performed to relieve the ureteral pressure by cutting through the ureteral wall at a location opposite the crossing vessel(s) to relax the ureteral lumen. Once performed, a stent is placed within the lumen until ureteral healing occurs.
FIGS. 1A and 1B are conceptual background drawings showing a portion 100 of a human urinary tract being obstructed at the UPJ 102. Referring to FIGS. 1A and 1B, in a human urinary tract 100, the ureters 104 and 106 transport urine from the kidneys, one of which is shown at 108, to the bladder 110. The femoral artery 112 and femoral vein 114 cross the ureter 104 at the UPJ 102.
As shown in FIG. 1B, on occasion, the femoral artery 112 and/or the femoral vein 114 exert pressure on the ureter 104 and restrict urine flow through the ureter lumen 116. Under normal circumstances, this may not cause discomfort. However, such obstruction may inhibit passage of a stone or stone fragment, such as the stone 118, from the kidney 108 to the bladder 110. As describe above, an endopylotomy can be performed to reduce the restriction in the ureter lumen 116. However, such a procedure is not without risk. For example, if a medical operator cuts the ureter lumen 116 on the inside wall portion 120 adjacent to the femoral artery 112 and vein 114, the femoral artery 112 and/or vein 114 may be inadvertently ruptured. Such a condition may become life threatening.
Some conventional endopylotomy devices and methods attempt to avoid cutting into the femoral artery 112 and/or femoral vein 114 by employing fluoroscopy to identify the location 104 of the femoral artery 112 and vein 114 and cutting at a location 122 opposite to the location 104. One disadvantage of this fluoroscopic approach is that it typically provides only two dimensional imaging. Another disadvantage is that appropriate fluoroscopy equipment is sometimes not readily available.